Berlin instruments of the old Egyptian
time of day destination

Herbert Rau, Berlin

It is the great merit of the Egyptologist Ludwig Borchardt to have analysed the theory of time
destination from the epoch of the Pharaohs and later on by means of the founds of showpieces and
fragments of Old Egyptian water-, sun- and star dials. 1)
A recent discussion of shadow measuring with the help of sundials in Old Egypt 2) and a
proposal of Mr. Schwarzinger got the referee to see in the Egyptian Museum of Berlin, in order
to do precise documentations about the concerning inventory pieces, respectively to have a look at the
card index. 3)

Borchardt differs four methods of the destination of the hours (daytime-) from the position of the sun and
one from the position of the stars:

Hieroglyphs : „I know the course of the sun, the moon and all stars to their site"

Owner : Horoskopen Horus, who was the son of the prince Har-woz and the (Queen) Esetcheb.

Literature : Borchardt in ÄZ 37(1899), p.10 f.

and Borchardt in ÄZ 48(1910/1911), p. 9-17

Inv. Nr. 14084,
6th century B.C.

Instrument: Sight rod

Material: Date palm frond

Site of the discovery : Abydos ?

Literature : Borchardt in ÄZ 37(1899), p.16
Both Instruments together (Inv. No 14084 and -14085) served to take aim at the stars.

Discussion about the Instruments for measuring of the height of the shadow with the help of a
horizontal plane to catch the shadow, to 1.2

Borchard proofs, that all time measuring-instruments - also the water clocks - had different sources of
errors. He writes in the end 1): „The old Egyptians had just no feeling for accuracy of time
determination...“. „They have measured neither equinoctial nor temporal hours.“

To let a shadow fall on the narrow ruler with its hour-marks at these ruler-sundials throughout the whole
year, Borchardt puts a yardstick with a five-edge cross-section, crosswise on the top peg. The ruler is
lying then in an East-West-direction with the top peg towards east during morning and to west in the
afternoon. The yardstick (crossbar) is situated always in North-South-position.

This assembled instrument in a T-shape had to be put into one of the three cross-section-positions,
in order to get a reasonable result (p.36 1)).

The resulting cross-section-positions of the more than 50 cm long yardstick on the relatively narrow top
peg of the just as short ruler were certainly unstable, especially the cross-section-position 1.

Borchardt himself writes: „The T-form and also the three positions of the cross-position cannot be
proved“ (p.36 1)). Did this T-form of Old-Egyptian sundials exist?

For a simple use of the ruler-sundial, without using the crosswise condition of a yardstick similar to
the later one with the oblique plane to catch the shadow, there is much to be said for the
following cases :

♦ The complicated change of the cross-wise positions and the instability of the composite
implement.

♦ The later sundials with oblique shadow collecting plane also had ray of light.

♦ The concerning characters (hieroglyphs) do not show a T-form.

♦

The charts of the day-times on the yardsticks (p.27 1)) only show the lengths of
the shadow in ells and hand's breadths, the first three and the last three day-times are
proved.

The example below shows, that during summer solstice the noon-altitude of the sun came up to the
6th daytime, during equinoctials almost came up the 5th/7th daytime and
during winter solstice came up the 4th/8th daytime of the instrument. Were
noon-altitudes of the sun for more than 40° no longer acceptable in Old Egypt for daily work, and
therefore not so interesting ?

All existing old-Egyptian findigs for measuring the time - at further places - ought to be measured and
proofed. The comment of the Egyptolgy is essential.